1 map ; negative, 21 x 32 cm.
This was a preliminary map showing one particular plan for the irrigation of the Columbia Basin. As noted in the title, this map represented the pumping plan, whereby a dam would be constructed at Grand Coulee and...

1 map ; negative : 32 x 27 cm. This was a preliminary map showing one particular plan for the irrigation of the Columbia Basin. As noted in the title, this map represented the pumping plan, whereby a dam would be constructed at Grand Coulee and...